T square



Dec. 23, 1952 W. T, NEMN 2,622,330

T SQUARE Filed May 12. 195o Patented Dec. 23, 1952 UNITED STATES orrlcs This invention relates to T squares `and vmore particularly to T squares of the type used in drafting rooms.

This is a continuation in'part of my copending applicationSerial No. 29,032, filed May 25, 1948.

In prior designs of T squares their bulkiness, that is, their peculiar shape and overall length and width dimensions, make themawkward and cumbersome to handle insofar as portability is concerned and they have always presented a problem when it is desired to package or transport them from place to place. The problem of carrying T squares has long perplexed students, engineers, draftsmen and the like who would like to carry them in a briefcase or in their pockets but because of their shape have not heretofore been able to do this. Not infrequently, when conventional T squares are transported from place to place they are damaged in transit because of their bulkiness. Accordingly, it is an object of this invention to provide a novel construction for a T square which may be used in a conventional manner, yet may be confined in a small space having overall dimensions not much greater than the head supporting the blade so that it can be conveniently packaged or carried from place to place.

Another object of the invention is to provide a T square of the above character that is simple in construction, that is sturdy and that is relatively inexpensive to manufacture.

Another object of the invention is to provide a T square in which the blade maybe coiled about the head with novel means for retaining the blade in coiled condition.

Another object of the invention is the provision of adjustable means mounted on a concavo-con- Vex blade capable of providing reinforcement for preselected portions of the side edges of the blade when the convex surface is facing the work surface.

Another object of the invention is the provision Aof a T square of the above character with novel means for reinforcing the blade adjacent the head when the blade is in its extended position.

Other objects and advantages of the invention will become apparent from the following detailed Idescription taken in connection with the accompanying drawings, in which- Figure 1 is an elevational view of one side of a 'T square embodying the present invention;

Fig. 2 is the opposite side view of the T square :shown in Figure 1;

Fig. 3 is a fragmentary View of the head of the Claims. (Cl. S13-#112) T- square showing the construction of the head;

Fig. #i is a sectional View taken substantially along the lines li-ll of Figure 1; v

Fig. 5 is a sectional view taken substantially along the line 5-5 of Figure 2;

2 Fig. 6 is a sectional view taken substantially along ythe line 6 6 of Figure 1, and

Fig. 'iis a perspective View of a T square with a blade coiled about the head and the latching meanssecuring the blade in coiled position.

Referring n oW to the drawings it will be seen that the T square comprises a head or handle portion I I and a relatively thinmetallic blade I2 secured to the head II in a cantilever fashion. In -this embodiment of the invention the head is formed by an elongated rectangular shaped member It. A similarly shaped member or clamping plate I3 in facerto face contiguous relation with the member It is provided to coact with the latter member to form a mounting for the blade I2 as described hereinafter. An edge IS of the member I3 and an edge I'I of the member I4 are formed so as to lie in asubstantially common plane, when the members are in the position shown in Figs. 1 and 2, and deiine straight edges shaped to abut against the side of a drafting board, notshown, in a conventional manner. By providing each member I3 and It with a surface shaped'to engage the side of the board either side of the blade may face the work` surface. As best seen in Fig. Sethe members I3 and It areassembled so thatthey may be rotated relative to each other and therebyrpermit angular adjustment of the blade with respect to the member nI3. Consequently the blademayV be adjusted to any desired angular position with respect tothe longitudinal axis of a drafting board. The members I3 and I4 may be formed from wood, synthetic resinous material or metal. Y

The blade I2 has a concavo-convex shaped cross section as best seen in Fig. 6 and is formed from resilient material sufliciently iiexible to permitthe blade to' be coiled about the head IIl as shownin Fig. 7 so that the roverall dimensions of the head and blade are not much greater than those of the head itself. As best seen in Fig. 6 the mounted end' of the blade I2 is received'in a recess 2B formed in the member I4 to face the member I3 and open on the edge II. The bottom I3 of the recess 20 is formed with a convexly curved configuration complementary to the concave surface of the blade I2 so `asrto provide a 'seat for the mounted end of the blade, '"IIhe recess '20 is also preshaped so that when the blade is in theA position shown in Fig. 6 the member I3 defines a clamp forn securing the mounted end of the blade in the recess. The members VI3 and I4 and the mounted end of the blade I2, see Fig. 6, are secured together, in rigid relation .as by a bolt I8 and a wing nut 2|. Where desired, washers .22 and 23 maybedisposed between the head of the bolt I9 and thememberlll and .between the wing nutv 2| Yand the member I3 `as shown in Fig. 6 in a conventional manner. A reinforcing member 2li also having a concave,-

3 convex cross section is mounted in side by side relation with the mounted end of the blade I2 and has a tongue portion 26 extending outwardly from the side I6 of the member I4 so as to reinforce the blade I2 and to help support the blade i2 in its extended position.

The concavo-convex cross sectional shape of the blade I2 is for the purpose of imparting rigidity to the blade so that when the blade is extended laterally of the member I4 as shownin Figure '1, the blade does not droop at its free -end when the T square is held up by the lmember I4 or bend laterally when an inking pen or the like engages the edges of the blade as in inking a drawing. The blade I2 may be of any desired length, the length in anygiven instance depend ing upon the width of the board with which the T square is being used. Itis to be understood, however, that for different lengths of the blade, different widths of the blade may also be required. The blade may be imprinted with any desired markings or scales. Also a set of blades of different lengths and widths may be provided for use with a given head II. To change blades the wing nut 2| and washer 23 are iirst removed so that the members I3 and I4 can be separated to effect removal of the old blade. The new blade is then inserted in the recess 23 with thev concave surface facing the bottom I8 and thereafter the members I3 and I4 are reassembled as shown in Fig. 6. The washer 23 and nut 2| are replaced and the nut 2| is screwed down tight.

When the concave surface of the blade I2 faces the work surface the side edges of the blade I2 are in intimate contact with the work surface and a straight line can be readily drawn by using the edges of the straight edge or blade as a guide for a drawing instrument. When the concave surface ofthe blade faces the work surface, however, the edges of the straight edge are spaced above the work surface and when pressure is applied to the edges, as by an inking pen or the like `pressed. against the edges, there is a tendency for the edges of the blade to buckle. If an edge of the blade touches the lwork surface during anA in king operation it will in all probability effect a smearing of the ink. One phase of the invention is concerned with means for supporting the blade to prevent buckling of the side edges thereof while utilizing the blade with the concave surface facing the Work surface so as to prevent the possibility of smearing ink by contact of the side edges with the work surface. TQ accomplish this a slider 3I is mounted on the blade I2 and is` shaped to provide a support for preselected portions of edgesof the blade. As best seen in Fig. the slider 3| has a body portion with a recess 32 for receiving the blade I 2. Preferabl-y the `recess has a convex bottom shaped to blade. The slider is retained on the blade by pad portions 33 integral with the body and spaced from the bottom of the recess to be engageable with the edges of the convex side of the blade as shown, `The pads also have hat outwardly facing surfaces 34 shaped to rest on the work surface and are of such dimensions that they rigidly support the edges of the blade immediately adjacent the slider in spaced relation to the work surface.

u The above construction permits the slider to be moved to any position between the head and the extreme outer end of the blade. When the slider is not being used it may be disposed in a recess 36, formed in the head, so as not to inter- -fere with the use of the T square when the consnugly intert with the concave `surface of the cave surface of the blade faces the work surface. At the extreme outer end of the blade, the latter is formed with tabs 31 on opposite side edges of the blade I2 deformed out of the plane of the blade I2 as be'st shown in Figure 1. The tabs 3l extend outwardly from the blade from the con- Vex surface side of the blade and in effect define legs for supporting the edgesof the end of the blade when the convex surface of the blade faces the workA surface. 'I'he tabs 3l also define stops for preventing inadvertent removal of the slider 3| from the blade I2. y

Another aspect of the invention is concerned with a latch 38 for retaining the blade in coiled relation about the head. As best shown in Figure 1 the latch includes a U-shaped member in face to face relation with the member I3 and comprising a bridging portion 39 and legs 4| and 42 spaced apart the Width of the blade I2; The leg 4I is -pivotally mounted on the member I3 as by a screw 43 and the leg 42 is provided with an aperture 44 shaped to receive a pin 46 mounted on the member I3 for securing the latch against row tation about the pivotpin 46. Th'e leg 42 may be kflexed outwardlyffrom the member I3 to effect entrance of the pin 46 in the aperture 44 or to disengage the leg from the `pin to permit movement of the latch about the .screw 43 to the position shown by dotted lines in Figure l. Preferably the bridging portion 39 is formed with a tab 4l, between the legs 4| and 42, shaped to be received in an aperture 43 formed at the cuter end of Athe blade I2 as best shown in Fig. 'l to positively secure the blade incoiled relation about the head.

The aforegoing construction is advantageous in that the T square may be confined in an extremely small package such asa briefcase or may be read.- ily placed in the pocket of a student, draftsman, or the like and carried from place to place as required. Another -advantage arising from this construction is the simplicity and ease of manufacture of this T'square. The material for the blade may be readily purchased in coil form. The only machining costs are those of shearing the blade I.2 to the desired length from the coil and forming the mounting hole, the holes 48 at the free end of the blade I2 and the tabs 3l. Consequently, this T square can be produced at a relatively loW cost. The latch insures that the blade is positively retained in a coiled position about the head, yet permits the blade to be readily uncoiled when it is desired to use the T square and also ready coiling of the blade about the head when it is desired to Astore the T square. The construction of the T square also permits either side of the blade to face the work surface. This has the advantage that when a drawing is being penciled the concave side of the blade may face the Work surface and the opposite edges of the blade will be in intimate contact with the work surface, thereby assuring the draftsman the greatest possible accuracy. When the convex surface faces the work surface the edges of the straight edge are spaced above the Work surface which is desirable, in some instances when inking, as the ink will not tend to run under the edges of the straight edge as is the case with conventional straight edges. The slider 3| provides a rigid support for the edges of the blade I2 When the convex surface of the blade faces the work surface, thereby assuring maximum effectiveness of the T square.

I claim:

l. A T square comprising a pair of opposed v elongated members in face to face relation and each having an edge shaped to engage the side of a drafting board, one of said members having a recess facing the other member and opening on the edge of said member shaped to engage the side of a drafting board, said recess having a convexly curved bottom, a relatively thin blade with an arcuate shaped cross section and having one end seated on said convexly curved bottom, said blade having its edges disposed in a common plane and its center portion spaced at one side of said plane, said arcuate shaped cross section providing suicient rigidity to the blade when it extends laterally from said members to be self-supporting and said blade being formed from sufficiently flexible material to permit the blade to be coiled up and releasable means for clamping said members and blade together to rigidly secure said end of the blade between said members.

2. A T square comprising a head, a relatively thin blade having a thin arcuate shaped cross section with the said edges of said blade being disposed in a common plane and the center portion of said blade being spaced at one side of said plane, said arcuate shaped cross section providig suficient rigidity to the blade when it extends laterally fromv the head to be self-supporting and said blade being formed from suiciently exible material to permit the blade to be coiled about said head, a latch comprising a bridging portion and legs spaced apart to receive the blade therebetween, means for pivotally mounting one leg of said latch in associated relation with the head to have the bridging portion swingable between a position in which it engages the coiled blade to maintain the latter in coiled relation about the head and a position in which the bridging portion is free of the blade to permit coiling and uncoiling thereof about the head and means engageable with said other leg for locking said bridging portion in the blade retaining position.

3. The combination recited in claim 2 in which the outer end of the blade is formed with an aperture and the bridging portion is formed with a tongue shaped to interi-lt in said aperture to hold the blade in coiled relation about the head.

4. A T square comprising a head, a thin flexible blade having a convexly curved section, means for mounting said blade on said head to have either the concave or the convex surface of the blade face a work surface, and adjustable means on said blade engaging the concave surface of the blade to rigidly support preselected edge portions of the blade in spaced relation to the work surface when the convex surface of the blade faces the work surface.

5. A T square comprising a head, a thin flexible blade having a concave-convex cross section and a mounted end and a free end. tabs at the free end of the blade facing outwardly from the convex surface, means for mounting said mounted end of the blade on said head to have either the concave or the convex face of the blade face the work surface, and a slider mounted on said blade being movable between the head and said tabs and engaging the concave face of the blade to rigidly support the edges of the blade in spaced relation to the work surface when the convex face of the blade faces the work surface.

6. A T square comprising a head, a thin flexible blade having a concavo convex cross section, means for mounting said blade on said head to have either the concave or the convex face face the work surface, and a slider mounted on said blade being movable between the head and the free end of the blade and shaped complementary to the concave face of the blade to snugly engage the same to rigidly support the edges of the blade in spaced relation to the work surface when the convex surface of the blade faces the latter.

'7. A T square comprising a head having a recess opening on one edge, a thin flexible blade having a concavo convex cross section and mounted and free ends, means for mounting said mounted end of the blade to be adjacent said recess, and a slider mounted on said blade adapted to be movable between a position in which it is received in said recess, to permit either the concave or the convex surface of the blade to face the work surface, and the free end of the blade and engaging the concave face of the blade to rigidly support the edges of the blade in spaced relation to the work surface when the convex face of the blade engages the work surface.

8. A T square comprising a head, a flexible blade attached at one end to the head and having a concavo-convex shaped cross section, the concave surface being disposed toward the head, said blade being bendable between a position in which it extends outwardly from the head in a self-supporting relation and a position in which it is Wrapped in a coil, means having an arcuate shaped surface engageable with the concave surface of the blade disposed between said blade and said head providing a support for the blade, and means extending through said blade and said support for securing the blade to the head.

9. A T square comprising a head having an edge shaped to abut against the side of a drafting board, a iiexible blade formed from relatively thin metallic material having a concavoconvex cross section, and means for securing one end of the blade to said head with the concave surface facing the head, said blade normally projecting outwardly from the head in a selfsupporting relation to overlie the drafting board in an operative position, the blade being coiled about itself and the head to a storage position.

10. A T square comprising a head, a flexible thin elongated blade of arcuate cross-section attached at one end to the head and normally projecting outwardly therefrom to overlie the drafting board in an operative position, said blade having an aperture adjacent the free end thereof, the blade being longitudinally bendable to be coiled about the head, and a releasable latch member pivotally mounted on the head engaging in the blade aperture adjacent the free end of the blade to maintain the blade coiled about the head.

WILLIAM T. NEIMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 514,685 Reber Feb. 13, 1894 742,013 Dunn Oct. 20, 1903 2,025,519 Lingg Dec. 24, 1935 2,033,026 Farrand Mar. 3, 1936 2,078,601 Cutting Apr. 27, 1937 2,358,451 Gardner Sept. 19, 1944 

